Feeding Your Fish Properly
How much and how often to feed — and why overfeeding, not underfeeding, is the more common danger to fish and water quality.
Also known as: Fish feeding, Overfeeding
Feeding seems simple but is where many new keepers go wrong. Fish need a varied, appropriate diet in small amounts; overfeeding fouls the water, spikes ammonia and causes more problems than the occasional missed meal. Matching food to the fish and feeding sparingly are the keys.
What it is
Fish are small and their stomachs are small; they need far less food than most people assume. The most common feeding mistake is overfeeding, which leaves uneaten food to rot, driving up ammonia and nitrate and fouling the water — often the hidden cause behind cloudy water and sick fish in an otherwise cycled tank.
How much. A good rule of thumb is to feed only what the fish finish in a couple of minutes, once or twice a day, removing or reducing anything left uneaten. Many healthy adult fish are fine with a weekly fasting day, which aids digestion and lets them clear their gut. Fry and some active species need more frequent small meals.
Match the food to the fish. Feed at the right level of the tank and to the right diet: floating flake or pellets for surface and mid-water fish, sinking pellets or wafers for bottom-dwellers like corydoras, and species-appropriate foods for carnivores (such as bettas) versus omnivores. A varied diet — a quality staple plus occasional frozen or live foods and, for some fish, vegetable matter — keeps colour and condition better than a single flake alone.
Watch and adjust. Feed by observation, not habit: healthy fish are eager and active at feeding, and a fish that consistently ignores food may be ill or the water may be off. When in doubt, feed a little less — a lean fish recovers from a missed meal far more easily than a whole tank recovers from an ammonia spike.
Worked example
A keeper's cycled community tank keeps showing traces of ammonia despite good filtration. The culprit is feeding: a large pinch of flake twice a day, most of it settling uneaten. They cut back to what the fish clear in about two minutes, add a sinking wafer for the corydoras, and fast the tank one day a week. Within days the leftover food and ammonia readings disappear, and the fish are just as healthy.
Related entries
Sources & further reading
- How Often and How Much to Feed Aquarium Fish — The Spruce Pets (article)
- Feeding Your Fish — Aqueon (article)